Cartesian coordinates robot

ABSTRACT

Provided is a rectangular coordinate type robot, in which spaced-apart first tables are provided with respective first moving units that are guided along the first tables, and a second table has its one end connected to the first moving unit provided for one of the first tables and the other end connected to the first moving unit provided for the other first table. The end portions of the second table and the first moving units are connected with each other via connecting members that have a rigidity in the movement direction of the first moving unit and a resiliency in the direction extending along the second table.

TECHNICAL FIELD

The present invention relates to a rectangular coordinate (Cartesiancoordinate) type robot.

BACKGROUND ART

In recent years, robots for use in mounting electronic components or thelike are required to have a longer stroke together with high speed andhigh accuracy.

Conventionally, as a robot for executing a variety of operations withhigh positional accuracy on a workpiece such as a board, there is therobot shown in FIG. 11 and FIG. 12.

This is provided with an X-axis table 52 supported in a cantilever styleon an Y-axis table 51. The X-axis table 52 can be positioned in anarbitrary position in the Y-direction. The X-axis table 52 is mountedwith a working head section 53 that can be positioned in an arbitraryposition in the X-direction. The working head section 53 is mounted witha position recognition means 54 for recognizing the position of aworkpiece W and a working member 55 such as a component suction nozzle,which are spaced apart at a specified distance D in the X-direction asshown in FIG. 12.

This robot recognizes with high accuracy the working position of theworking head section 53 by means of the position recognition means 54 bymoving the working head section 53 into the working position of theworkpiece W by means of the Y-axis table 51 and the X-axis table 52, andmoves the working head section 53 by means of the Y-axis table 51 or theX-axis table 52 on the basis of the recognized working position and theabove-mentioned distance D, thereby guiding the working member 55 intothe working position for the execution of the operation.

The X-axis table 52 is supported in a cantilever style on the Y-axistable 51, and this causes an issue that vibration tends to occur whenthe X-axis table 52 is made to have a long stroke in correspondence tothe workpiece W and an issue that it takes a period of time to positionthe working head section 53 when stopping a high-speed operation. A boltfor fastening the Y-axis table 51 to the X-axis table 52 tends to becomeloose. There is a further issue that the positioning accuracy of theworking head section 53 is significantly reduced by the yawing androlling of the Y-axis table 51.

A rectangular coordinate type robot (Japanese Laid-Open PatentPublication No. 3-221385) that we have already proposed in order tosolve the above-mentioned issues has a construction as shown in FIG. 13and FIG. 14.

A pair of Y-axis tables 1 and 2 are arranged parallel to each other, andthe Y-axis tables 1 and 2 are provided with first moving units 4 and Sthat move while being guided along the Y-axis tables 1 and 2,respectively.

Between the Y-axis tables 1 and 2 is provided an X-axis table 3perpendicular to the Y-axis tables 1 and 2. The X-axis table 3 isprovided with a second moving unit 21 that is guided along the X-axistable 3.

One end portion of the X-axis table 3 and the first moving unit 4located on the side of the one Y-axis table 1 are engaged with eachother while being pivotal around the axes that are perpendicular to theY-axis and X-axis tables. The other end portion of the X-axis table 3and the first moving unit 5 located on the side of the other Y-axistable 2 are engaged and supported with each other while being pivotalaround the axes that are perpendicular to the Y-axis and X-axis tablesand slidable in the axial direction of the X-axis table 3.

The second moving unit 21 is provided with a workpiece positionrecognition means 25 and a working member 26.

In more detail, the Y-axis tables 1 and 2 are internally provided withthreaded shafts (implemented by, for example, ball screws) 6 and 7 andmotors 8 and 9 for rotating these threaded shafts 6 and 7. The firstmoving units 4 and 5 are meshed with the respective threaded shafts 6and 7 via nuts (not shown).

The X-axis table 3 is supported and engaged pivotally with the firstmoving units 4 and 5 located on the Y-axis tables 1 and 2 and slidablyin the axial direction of the X-axis table 3.

That is, the first moving units 4 and 5 located on the Y-axis tables 1and 2 have their center portions provided with engagement shafts 11 and12 that are protruding in the vertical direction (in the directionperpendicular to both the Y-axis table and the X-axis table) as shown inFIG. 15.

To one end portion of the X-axis table 3 is fixed a connecting member 14that is pivotally engaged with the engagement shaft 11 of the firstmoving unit 4 via a bearing 13. To the other end portion of the X-axistable 3 are fixed fixing sections 15a of a slide block 15 as shown inFIG. 16, and a movable section 15b that is made slidable between thefixing sections 15a of the slide block 15 and is pivotally engaged withthe engagement shaft 12 of the first moving unit 5 via a bearing 16.

Therefore, by driving the motors 8 and 9 in synchronism, the X-axistable 3 can be moved into an arbitrary position along the Y-axis tables1 and 2 via the first moving units 4 and 5.

The second moving unit 21 provided on the X-axis table 3 is providedwith a threaded shaft (implemented by, for example, a ball screw) 22 anda motor 23 for rotating this threaded shaft 22 arranged inside theX-axis table 3 as shown in FIG. 13, and the second moving unit 21 ismeshed with the threaded shaft 22 via a nut 24.

The second moving unit 21 has its one side surface provided with aworking member mounting plate 27 that is movable in the axial directionof the X-axis table 3. The second moving unit 21 is provided with athreaded shaft (implemented by, for example, a ball screw) 29 and amotor 30 for rotating this threaded shaft 29, while a nut 28 attached tothe back surface of the working member mounting plate 27 is meshed withthe threaded shaft 29.

The working member mounting plate 27 is mounted with the workpieceposition recognition means (e.g., a camera) 25 and a workpiece workingtool, which is an example of the working member 26. The referencenumerals 31 and 32 denote cable units for transmitting a power signaland a control signal.

However, the rectangular coordinate type robot shown in FIG. 13 throughFIG. 16 has the disadvantages of a deterioration in accuracy due to thelooseness of the rotating portions occurring when performing thepositioning in the Y-axis direction of a Y₁ -axis and a Y₂ -axis as wellas the disadvantage that it takes a period of time to settle thepositioning.

It has also been unable to provide a sufficient added weight of therotational and slide mechanisms for the issue in terms of space.

Furthermore, in regard to the positioning accuracy, the component sizehas been reduced and component lead pitch has been reduced (0.3-mmpitch) in recent years, and accordingly, a mounting accuracy of ±25 μmis required. However, there has been a vibration of the maximumamplitude of about 30 μm in the positioning stage according to theconventional system, and a settling time (time to the achievement ofsettlement within a range of ±5 μm) of about 400 msec has currently beenrequired.

The present invention has the object of providing a rectangularcoordinate type robot capable of executing a positioning operationwithout reducing the rigidity when moving an X-axis table in a Y-axisdirection of a Y₁ -axis and a Y₂ -axis.

SUMMARY OF THE INVENTION

The rectangular coordinate type robot of the present invention is arectangular coordinate type robot, characterized in that first tablesjuxtaposed with a space therebetween are provided with respective firstmoving units that are guided along the first tables, and a second tablehas its one end connected to the first moving unit provided for one ofthe first tables and the other end connected to the first moving unitprovided for the other first table. The end portions of the second tableand the first moving units are connected with each other via connectingmembers that have a rigidity in a movement direction of the first movingunit and a resiliency in the direction extending along the second table.

According to the present invention, a rectangular coordinate type robotthat can execute positioning without reducing the rigidity when movingthe second table in the Y25 axis direction can be obtained.

BRIEF DESCRIPTION OF DRAWINGS

These and other aspects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1A is a view showing the construction of a component mountingapparatus mounted with a rectangular coordinate type robot according toa first embodiment of the present invention;

FIG. 1B is a view for explaining two Y-axis tables of the componentmounting apparatus of FIG. 1A, the tables deviating from the parallelposition thereof;

FIG. 2 is a front view of the rectangular coordinate type robot of thefirst embodiment;

FIG. 3 is an exploded perspective view showing a first connectingportion of the first embodiment;

FIG. 4 is an exploded perspective view showing a second connectingportion of the first embodiment;

FIG. 5 is a plan view of a connecting plate used for the firstconnecting portion of the first embodiment;

FIG. 6 is a plan view of a connecting plate used for the secondconnecting portion of the first embodiment;

FIG. 7 is a schematic view for explaining the effect of the firstembodiment;

FIG. 8 is a plan view of a connecting plate used for a second connectingportion of a second embodiment;

FIG. 9 is a plan view of a connecting plate used for a second connectingportion of a third embodiment;

FIG. 10 is a plan view of a connecting plate used for a secondconnecting portion of a fourth embodiment;

FIG. 11 is a perspective view of a rectangular coordinate type robot ofa prior art example;

FIG. 12 is a plan view of the same prior art example;

FIG. 13 is a perspective view of a rectangular coordinate type robot ofanother prior art example;

FIG. 14 is a plan view of the same prior art example;

FIG. 15 is a perspective view showing the structure of a connectingportion of the same prior art example; and

FIG. 16 is a sectional view showing the structure of the connectingportion of the same prior art example.

DETAILED DESCRIPTION OF THE INVENTION

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like reference numeralsthroughout the accompanying drawings.

The outline of the present invention will be described first.

A rectangular coordinate type robot according to a first aspect of thepresent invention is a rectangular coordinate type robot characterizedby providing: a pair of first tables that are juxtaposed with a spacetherebetween and provided with first moving units, respectively, guidedalong the first tables; a second table having its one end connected tothe first moving unit provided for one of the first tables and the otherend connected to the first moving unit provided for the other firsttable; and a second moving unit that moves while being guided along thesecond table and is provided with a working member. At least oneconnecting portion of a of one end of the second table and the firstmoving unit and a connecting portion of the other end of the secondtable and the first moving unit is connected via a connecting memberhaving a rigidity in a movement direction in which the first moving unitmoves and a resiliency in a direction extending along the second table.

According to this construction, movement can be made smooth by reducinga load in the driving stage with respect to the errors of the Y₁ -axisand the Y₂ -axis in the X-axis direction due to the resiliency of theconnecting member. In addition, since the connecting members have therigidity in the direction of the Y₁ -axis and the Y₂ -axis, the settlingtime in the positioning stage can be reduced and the movement operationcan be achieved without deteriorating the positioning accuracy.

A rectangular coordinate type robot according to a second aspect of thepresent invention is a rectangular coordinate type robot characterizedby providing: a pair of first tables that are juxtaposed withinterposition of an interval and provided with first moving units,respectively, guided along the first tables; a second table having itsone end connected to the first moving unit provided for one of the firsttables and the other end connected to the first moving unit provided forthe other first table; and a second moving unit that moves while beingguided along the second table and is provided with a working member. Oneend of the second table is fixed to the first moving unit, and aconnecting portion of the other end of the second table and the firstmoving unit is connected via a connecting member having a rigidity in amovement direction in which the first moving unit moves and a resiliencyin a direction extending along the second table.

A rectangular coordinate type robot according to a third aspect of thepresent invention is based on the first or second aspect andcharacterized in that the connecting member is provided by aplate-shaped block that has its center portion made to serve as a fixedside to be fixed to the first moving unit, the plate-shaped block hasits peripheral portion made to serve as a movable side to be fixed tothe second table, and through holes are formed in the plate-shaped blockso that the fixed side and the movable side of the plate-shaped blockare connected via thinned portions.

A rectangular coordinate type robot according to a fourth aspect of thepresent invention is based on the third aspect and characterized in thatthe through holes formed through the plate-shaped block so that thefixed side and the movable side of the plate-shaped block are connectedvia the thinned portions are slit grooves.

A rectangular coordinate type robot according to a fifth aspect of thepresent invention is based on the third or fourth aspect andcharacterized in that the thinned portions are portions that extend inthe movement direction in which the first moving unit moves so as tohave the rigidity in the movement direction and is thin in a directioncrossing the movement direction so as to have the resiliency in thecrossing direction.

A rectangular coordinate type robot according to a sixth aspect of thepresent invention is based on any one of the first through fifth aspectsand characterized in that the connecting members have rigidity in themovement direction of the first moving unit and have resiliency in thedirection extending along the second table, for reducing slidingresistance by allowing elastic deformation in response to a deviation inthe direction extending along the second table due to mounting andprocessing accuracy of the pair of first tables.

The rectangular coordinate type robots according to embodiments of thepresent invention will be described below with reference to FIG. 1Athrough FIG. 10.

<First Embodiment>

FIG. 1A through FIG. 6 show a rectangular coordinate type robot A of afirst embodiment of the present invention.

FIG. 1A shows a component mounting apparatus mounted with therectangular coordinate type robot A of the first embodiment of thepresent invention. The basic structure of the rectangular coordinatetype robot A includes a pair of Y-axis tables 103 and 104 that serveexamples of the first tables arranged parallel to each other and anX-axis table 102 that serves as an example of the second table arrangedbetween the Y-axis tables 103 and 104, similar to the prior art exampleshown in FIG. 12 and FIG. 13. The concrete structures of the connectingportions of the Y-axis tables 103 and 104 and the X-axis table 102 aredifferent from those of the above-mentioned prior art example.

The overall structure of the component mounting apparatus will bedescribed first.

A head section 101 that serves as an example of the second moving unitmounted with a suction nozzle 101a that serves as an example of theworking member for sucking and holding components etc. by means of avacuum pressure or the like for the mounting work or the like is movablymounted on the X-axis table 102 in the direction (X-axis direction)extending along the X-axis table 102. The X-axis table 102 has a device(a motor, for example) for moving the head section 101 in the X-axisdirection with the device built into the X-axis table 102.

The Y-axis direction tables 103 and 104 have devices (motors, forexample) for moving the X-axis table 102 in the Y-axis of the Y₁ -axisextending along the Y-axis table 103 and the Y-axis direction of the Y₂-axis extending along the Y-axis table 104 with the devices built intothe Y-axis tables 103 and 104.

The Y-axis table 103 and one end of the X-axis table 102 are connectedtogether via a first connecting portion 105. The Y-axis table 104 andthe other end of the X-axis table 102 are connected together via asecond connecting portion 106.

The reference numeral 107 denotes an electronic component supplying unitfor supplying electronic components arranged in a tape-shaped form,while the reference numeral 108 denotes a recognition unit. Therecognition unit 108 recognizes the suction posture and other conditionsof the electronic component sucked by the suction nozzle mounted on thehead section 101 from the electronic component supplying unit 107, andthe head section 101 executes a correcting operation of the suctionposture and other conditions on the basis of the recognized data.

The reference numeral 109 denotes a conveyance section for moving aboard, or the workpiece from the upstream side to the downstream side,while the reference numeral 110 denotes a tray lifter for taking out asupply tray on which components are set.

FIG. 2 shows a relation between the Y-axis tables 103 and 104, theX-axis table 102, and the first and second connecting portions 105 and106.

The first connecting portion 105 is constructed as shown in FIG. 3.

The first connecting portion 105 is constructed by a first moving unit111 driven along the Y-axis table 103, a bracket 112, a fixing plate113, and a connecting plate 114. In concrete, the fixing plate 113 isattached to the upper surface of the first moving unit 111 by insertinga bolt 113b into each of four holes 113a bored through the fixing plate113, and the connecting plate 114 is attached to the upper surface ofthe fixing plate 113 by inserting a bolt (not shown) from each of fourholes 114a (see FIG. 5) bored through the center portion of theconnecting plate 114 into each of four threaded holes 113c formed at thecenter portion of the fixing plate 113. The bracket 112 is attached tothe upper surface of the connecting plate 114 by inserting a bolt (notshown) from each of four holes 112a bored through the bracket 112 intoeach of four threaded holes 114b formed in the peripheral portion of theconnecting plate 114, and one end of the X-axis table 102 is mounted onthe bracket 112.

The second connecting portion 106 is constructed as shown in FIG. 4.

The second connecting portion 106 is constructed by a first moving unit115 driven along the Y-axis table 104, a bracket 116, a fixing plate117, and a connecting plate 118-1. In concrete, the fixing plate 117 isattached to the upper surface of the first moving unit 115 by insertinga bolt 117b into each of four holes 117a bored through the fixing plate117, and the connecting plate 118-1 is attached to the upper surface ofthe fixing plate 117 by inserting a bolt (not shown) from each of fourholes 118a (see FIG. 6) bored at the center portion of the connectingplate 118-1 into each of four threaded holes 117c formed at the centerportion of the fixing plate 117. The bracket 116 is attached to theupper surface of the connecting plate 118-1 by inserting a bolt (notshown) from each of four holes 116a bored through the bracket 116 intoeach of four threaded holes 118b formed in the peripheral portion of theconnecting plate 118-1, and the other end of the X-axis table 102 ismounted on the bracket 116.

As also shown in FIG. 6, the connecting plate 118-1 is formed to havethinned portions 118f and 118g, or an example of the thin connectingmember that extends along the Y₂ -axis direction and has a smallthickness in the direction perpendicular to the Y₂ -axis direction byboring semicircular holes 118d and 118e with part left on theperipheries of the center portion 118c where four holes 118a are bored.In concrete, a tool steel SK7 having a plate thickness of 12 mm washardened to be used as the connecting plate 118-1.

With this arrangement, if the Y-axis table 104 is mounted while beinginclined by an error Δx from the parallel position (position of theimaginary line) relative to the Y-axis table 103 as shown in theschematic views of FIG. 7 and FIG. 1B when mounting the Y-axis tables103 and 104, then the thinned portions 118f and 118g of the connectingplate 118-1 that are formed so as to have a small thickness in thedirection perpendicular to the Y₂ -axis direction are deformed by theirown resiliency to reduce the load in the driving stage, thereby allowingthe X-axis table 102 to smoothly move in the directions of the Y₁ and Y₂-axes.

Furthermore, the thinned portions 118f and 118g are formed so as toextend in the Y₂ -axis direction parallel to the Y₁ -axis direction.Therefore, the thinned portions have rigidity in the directions of theY₁ and Y₂ -axes, and this allows the settling time in the positioningstage to be reduced and allows the operation to be executed withoutdeteriorating the positioning accuracy.

Therefore, if this rectangular coordinate type robot is used as amovement mechanism of the component suction nozzle 101a of the mountingapparatus for mounting components on a board, then the thinned portions118f and 118g are deformed by their own resiliency even when, forexample, the Y-axis table 104 is mounted while being inclined by theerror Δx from the parallel position (position of the imaginary line)relative to the Y-axis table 103, so that the load can be reduced in thedriving stage and the X-axis table 102 can smoothly move in thedirections of the Y₁ and Y₂ -axes. Consequently, the movement of thecomponent suction nozzle 101a can be made smooth without beinginfluenced by the mounting error. Furthermore, the thinned portions 118fand 118g allow the reduction of the settling time in the positioningstage of the suction nozzle 101a and allows the execution of theoperation without deteriorating the positioning accuracy of the suctionnozzle 101a with respect to the component suction position and the boardmounting position relative to the component supply tray or the componentsupply unit.

If the moving unit that moves in the Y₁ -axis direction and the movingunit that moves in the Y₂ -axis direction erroneously run in thecomponent mounting apparatus, then the resiliency provided on the Y₂-axis side can effectively prevent the damage of the connectingportions.

<Second Embodiment>

FIG. 8 shows a connecting plate 118-2 of a rectangular coordinate typerobot according to a second embodiment of the present invention, and theother components are the same as those of the rectangular coordinatetype robot of the first embodiment. According to the connecting plate118-1 of the rectangular coordinate type robot of the first embodiment,the semicircular holes 118d and 118e are bored for the formation of thethinned portions 118f and 118g. In contrast to this, the connectingplate 118-2 of the rectangular coordinate type robot of this secondembodiment differs from the rectangular coordinate type robot of thefirst embodiment in the shape of the holes and the number of themounting holes to be bored for the formation of the thinned portions. Inconcrete, each of the holes 118d and 118e for the formation of thethinned portions of the connecting plate 118-2 has a bracket "]" shapeinstead of the semicircular shape and there are provided two holes 118ainstead of the four holes. The fixing plate 117 is formed with holes117c corresponding to the holes 118a.

<Third Embodiment>

FIG. 9 shows a connecting plate 118-3 of a rectangular coordinate typerobot according to a third embodiment of the present invention, and theother components are the same as those of the rectangular coordinatetype robot of the first embodiment. According to the connecting plate118-1 of the rectangular coordinate type robot of the first embodiment,the center portion 118c is supported by the thinned portions 118f and118g. In contrast to this, according to the connecting plate 118-3 ofthe rectangular coordinate type robot of this third embodiment, a fixingportion 118c₁ supported by thinned portions 118f₁ and 118g₁ and a fixingportion 118c₂ supported by thinned portions 118f₂ and 118g₂ are fixed tothe first moving unit 115. According to the connecting plate 118-3, eachof the shapes of holes 118d₁, 118e₁, 118d₂ and 118e₂ bored for theformation of the thinned portions is roughly bracket "]" shape, andthere are provided two holes 118a. The fixing plate 117 is formed withholes 117c corresponding to the holes 118a.

<Fourth Embodiment>

FIG. 10 shows a connecting plate 118-4 of a rectangular coordinate typerobot according to a fourth embodiment of the present invention, and theother components are the same as those of the rectangular coordinatetype robot of the first embodiment. According to the connecting plate118-1 of the rectangular coordinate type robot of the first embodiment,the semicircular holes 118d and 118e are bored so that the centerportion 118c is supported by the thinned portions 118f and 118g. Incontrast to this, according to the connecting plate 118-4 of therectangular coordinate type robot of this fourth embodiment, two throughslit grooves 119 of a width of about 0.2 mm are formed by a laser beamthrough a plate-shaped block to form thinned portions 118f₃ and 118g₃ sothat the fixed side and the movable side of the plate-shaped block areconnected together via the thinned portion, and a center portion 118c₃is formed in the portion that is roughly surrounded by the two slitgrooves 119. The fixing plate 117 is formed with holes 117ccorresponding to the holes 118a.

A resiliency can be provided merely by the cutting with the laser or thelike, and therefore, cost reduction can be achieved.

Only the second connecting portion 106 out of the first and secondconnecting portions 105 and 106 is made to have the rigidity in thedirection of the Y-axis table and the resiliency in the directionextending along the X-axis table 102 in each of the aforementionedembodiments. However, both the first and second connecting portions 105and 106 may also be made to have the rigidity in the direction of theY-axis tables and the resiliency in the direction extending along theX-axis table 102. In this case, it is also acceptable to employ plateshaving different strength of resiliency as exemplified by the employmentof a plate having a bending stress of 982 kgf/cm² and a deflection of0.2 mm for the connecting plates 118-1 through 118-4 and the employmentof a plate having a bending stress of 1969 kgf/cm² and a deflection of0.05 mm similar to the constructions of the connecting plates 118-1through 118-4 in place of the connecting plate 114.

As described above, according to the present invention, the connectingmember for connecting the first table with the second table has rigidityin the movement direction of the first moving unit that can move alongthe first table and resiliency in the direction extending along thesecond table. Therefore, this connecting member becomes a rigid body inthe movement direction of the second table relative to the first table,so that the member can achieve the movement and the positioningoperation of the second table without deteriorating the accuracy norprolonging the settling time nor increasing the sliding resistance orthe like by being elastically deformed with respect to the deviation inthe direction extending along the second table due to the mounting ofthe pair of first tables and the processing accuracy.

The entire disclosure of Japanese Patent Application No. 8-246764 filedon Sep. 19, 1996, including specification, claims, drawings, and summaryis incorporated herein by reference in its entirety.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

What is claimed is:
 1. A rectangular coordinate type robot, comprising:apair of first tables that are juxtaposed with a space therebetween andprovided with first moving units, respectively, guided along the firsttables; a second table having one end connected to the first moving unitprovided for one of the first tables and the other end connected to thefirst moving unit provided for the other first table; and a secondmoving unit that is movable along the second table and is provided witha working member, wherein at least one of a first connecting portion ofsaid one end of the second table and one of the first moving units and asecond connecting portion of the other end of the second table and theother of the first moving units is connected via a connecting memberhaving a rigidity in a movement direction in which the correspondingfirst moving unit moves and a resiliency in a direction extending alongthe second table.
 2. A rectangular coordinate type robot as claimed inclaim 1, whereinthe connecting member is provided by a plate-shapedblock that has its center portion made to serve as a fixed side to befixed to the corresponding first moving unit, the plate-shaped block hasits peripheral portion made to serve as a movable side to be fixed tothe second table, and through holes are formed in the plate-shaped blockso that the fixed side and the movable side of the plate-shaped blockare connected via thinned portions.
 3. A rectangular coordinate typerobot as claimed in claim 2, whereinthe through holes formed through theplate-shaped block so that the fixed side and the movable side of theplate-shaped block are connected via the thinned portions are slitgrooves.
 4. A rectangular coordinate type robot as claimed in claim 3,whereinthe thinned portions are portions that extend in the movementdirection in which the corresponding first moving unit moves so as tohave the rigidity in the movement direction and are thin in a directioncrossing the movement direction so as to have the resiliency in thecrossing direction.
 5. A rectangular coordinate type robot as claimed inclaim 1, whereinboth of said first and second connecting portionsprovide connection via connecting members, and both of the connectingmembers have the rigidity in the movement direction of the correspondingfirst moving unit and have the resiliency, capable of reducing a slidingresistance by being elastically deformed in response to a deviation inthe direction extending along the second table due to mounting andprocessing accuracy of the pair of first tables, in the directionextending along the second table.
 6. A rectangular coordinate type robotas claimed in claim 4, whereinthe thinned portions are portions thatextend in the movement direction in which the corresponding first movingunit moves so as to have the rigidity in the movement direction and arethin in a direction crossing the movement direction so as to have theresiliency in the crossing direction.
 7. A rectangular coordinate typerobot as claimed in claim 3, whereinboth of said first and secondconnecting portions provide connection via connecting members, and bothof the connecting members have the rigidity in the movement direction ofthe corresponding first moving unit and have the resiliency, capable ofreducing a sliding resistance by being elastically deformed in responseto a deviation in the direction extending along the second table due tomounting and processing accuracy of the pair of first tables, in thedirection extending along the second table.
 8. A rectangular coordinatetype robot as claimed in claim 4, whereinboth of said first and secondconnecting portions provide connection via connecting members, and bothof the connecting members have the rigidity in the movement direction ofthe corresponding first moving unit have the resiliency, capable ofreducing a sliding resistance by being elastically deformed in responseto a deviation in the direction extending along the second table due tomounting and processing accuracy of the pair of first tables, in thedirection extending along the second table.
 9. A rectangular coordinatetype robot as claimed in claim 5, whereinboth of said first and secondconnecting portions provide connection via connecting members, and bothof the connecting members have the rigidity in the movement direction ofthe corresponding first moving unit and have the resiliency, capable ofreducing a sliding resistance by being elastically deformed in responseto a deviation in the direction extending along the second table due tomounting and processing accuracy of the pair of first tables, in thedirection extending along the second table.
 10. A rectangular coordinatetype robot as claimed in claim 9, whereinboth of said first and secondconnecting portions provide connection via connecting members, and bothof the connecting members have the rigidity in the movement direction ofthe corresponding first moving unit and have the resiliency, capable ofreducing a sliding resistance by being elastically deformed in responseto a deviation in the direction extending along the second table due tomounting and processing accuracy of the pair of first tables, in thedirection extending along the second table.
 11. A rectangular coordinatetype robot, comprising:a pair of first tables that are juxtaposed with aspace therebetween and provided with first moving units, respectively,guided along the first tables; a second table having one end connectedto one of the first moving units provided for one of the first tablesand the other end connected to the other of the first moving unitprovided for the other first table; and a second moving unit that moveswhile being guided along the second table and is provided with a workingmember, wherein said one end of the second table is fixed to said one ofthe first moving units, and a connecting portion of the other end of thesecond table and said other of the first moving units is connected via aconnecting member having a rigidity in a movement direction in whichsaid other of the first moving units moves and a resiliency in adirection extending along the second table.
 12. A rectangular coordinatetype robot as claimed in claim 10, whereinthe connecting member isprovided by a plate-shaped block that has its center portion made toserve as a fixed side to be fixed to said other of the first movingunits, the plate-shaped block has its peripheral portion made to serveas a movable side to be fixed to the second table, and through holes areformed in the plate-shaped block so that the fixed side and the movableside of the plate-shaped block are connected via thinned portions.
 13. Arectangular coordinate type robot as claimed in claim 12, whereinthethrough holes formed through the plate-shaped block so that the fixedside and the movable side of the plate-shaped block are connected viathe thinned portions are slit grooves.
 14. A rectangular coordinate typerobot as claimed in claim 2, whereinthe connecting member having therigidity in the movement direction of said other of the first movingunits has the resiliency, capable of reducing a sliding resistance bybeing elastically deformed in response to a deviation in the directionextending along the second table due to mounting and processing accuracyof the pair of first tables, in the direction extending along the secondtable.
 15. A rectangular coordinate type robot as claimed in claim 7,whereinthe connecting member having the rigidity in the movementdirection of said other of the first moving units has the resiliency,capable of reducing a sliding resistance by being elastically deformedin response to a deviation in the direction extending along the secondtable due to mounting and processing accuracy of the pair of firsttables, in the direction extending along the second table.
 16. Arectangular coordinate type robot as claimed in claim 8, whereintheconnecting member having the rigidity in the movement direction of saidother of the first moving units has the resiliency, capable of reducinga sliding resistance by being elastically deformed in response to adeviation in the direction extending along the second table due tomounting and processing accuracy of the pair of first tables, in thedirection extending along the second table.